Metastatic dissemination and outgrowth of cancers is responsible for almost 90% of cancer-related deaths. The current ability to treat metastatic lesions using standard therapy is extremely limited, as they are often inoperable and resistant to chemotherapies. Understanding of the drivers of this process and identifying novel ways to target metastatic disease is therefore of critical importance. Several lines of evidence in melanoma and lung cancer models suggest that LKB1-deficiency is a strong promoter of metastasis, but the mechanisms by which LKB1 loss promotes lung tumor metastasis have not been well defined. Our preliminary data suggest that Wnt5a is upregulated in LKB1-deficient contexts and given its role in invasion and metastasis in other cancers, as well as elevated expression in metastatic human lung cancer, it is possible that Wnt5a is a downstream mediator of LKB1 dependent metastasis and represents a promising therapeutic target for this disease. In this proposal, the role of Wnt5a in LKB1-deficient lung cancer metastasis will be addressed both in vitro and in vivo as well as their therapeutic benefits of targeting Wnt5a for treatment of NSCLC. First, both genetic deletion and viral-mediated overexpression will be used to evaluate the contribution of Wnt5a to invasion and metastatic phenotypes in vitro, as well as address the LKB1-dependency on Wnt5a to promote metastasis. The consequences of Wnt5a modulation on the ability of NSCLC cells to metastasize in vivo will be addressed using orthotopic allograft transplants and endogenous deletion in genetically engineered murine models of NSCLC using CRISPR technology. Additional studies are designed to test the therapeutic efficacy of Wnt5a antagonists to inhibit tumor growth and metastasis in vivo. Lastly, the experiments proposed in this fellowship will elucidate the signaling pathways activated downstream of Wnt5a that are critical for metastasis, both through evaluation of known Wnt5a signaling components and RNA sequencing to identify novel downstream regulators of metastasis. Together, these studies will define the role of Wnt5a in LKB1-deficient metastasis and address the therapeutic benefit of targeting Wnt5a signaling in NSCLC metastasis, with the potential for enhanced efficacy in patients with tumors harboring LKB1 mutations.